In view of improper eating habits in the modern rich life, diet-caused diseases are increasing. Bioelectrochemical measurement systems with high reliable accuracy for those who require long-term monitoring health status (such as glucose, lipids, etc.) have gradually become an indispensable tool for life.
Conventional electrochemical and biochemical measurement systems may present significant errors for measurement results. That is because blood composition includes interference components to the measurement results. The most representative interference components that interfere are the proportion of red blood cells in the blood (i.e., hematocrit, hereinafter referred to as HCT). The blood HCT is an important parameter leading to occurrence of errors in measurement results. For example, in operating measurements of blood glucose, cholesterol, uric acid and blood clotting speed, red blood cells may impede reaction between the blood and an enzyme, causing the measurement result of high HCT presented lower than its actual value, while the measurement result of low HCT presented higher than its actual value.
With reference to current background art, there are a variety of technical solutions to solve the problems caused by HCT. For example, U.S. Pat. No. 5,628,890, the entity of which is incorporated herein by reference, discloses a test strip for an electrochemical system. A filter layer is disposed on the test strip to separate the red blood cells from the blood sample to be tested. However, the method disclosed in this patent has drawbacks such as difficulty to process the test strip, high cost, long measurement time taken, and large amount of measurement blood needed.
U.S. Pat. No. 7,407,811 discloses a method for detecting HCT and correcting the concentration of the blood to be tested. AC signals with frequencies in a range of 1 Hz-20 KHz are provided to test the blood sample. The phase angle and admittance magnitude of the blood can be measured and HCT values in the blood can be calculated therefrom. However, the technical solutions disclosed in this patent need repeated providing of two to five signals with different frequencies to the tested blood. It is a practical disadvantage that the blood HCT is measured by signals with different frequencies, resulting in long overall reaction time, operational difficulties, and increased power consumption.
In addition, U.S. Pat. No. 8,480,869 discloses an HCT measurement method using a redox reaction in which ferricyanide or ferrocyanide is disposed on electrochemical test strip electrodes. After ferricyanide or ferrocyanide reacts with red blood cells, the HCT value can thereby be measured. However, the redox agents disclosed in U.S. Pat. No. 8,480,869 may interfere with other enzymes on the electrochemical test strip, resulting in a distortion of the measurement results. Further, although both U.S. Pat. Nos. 7,407,811 and 8,480,869 disclose methods to measure HCT values of the blood, other components in the blood can also pose a threat to the accuracy of HCT measurement. Moreover, although U.S. Pat. No. 5,628,890 discloses that the red blood cells can be separated from the blood for testing, the presence of HCT cannot be completely filtered out. Accordingly, HCT measurement systems with high accuracy and reliability are needed for the industry based on overcoming the above disadvantages of conventional technologies.